1. Field of the Invention
This invention relates to a data processing system having two independent read only memory program storage areas, and more particularly to a parallel processing type of data processing system.
2. Prior Art
In conventional data processing systems of the parallel processing type, the dominant limitation on processing rate is the access time of the read only memory. In many applications, such as arithmetic operations in a calculator, the limited instruction power combined with an instruction cycle rate determined by the read only memory access time produces an unsatisfactorily slow computation speed. While the ROM access time may be reduced to increase the computation speed, the result is a larger size read only memory array, and therefore a more costly device. Alternatively, the instruction set may be enhanced, thus increasing computation speed, but again at the sacrifice of requiring a larger instruction decode area for the semiconductor circuit.